Metal alkoxides reaction with carbon monoxide

Alkali metal alkoxides catalyse the alcoholysis of esters, by a mechanism analogous to basic hydrolysis. Additionally, alkoxides catalyse the reaction of alcohols with carbon monoxide to give formate esters ... 

In the absence of hydrogen, a catalytic reaction of carbon monoxide and an alcohol produces alkyl formate (Eq. 7.7). The catalyst involved is an alkali metal alkoxide alone or together with a transition metal carbonyl cluster, e.g. Ru3(CO)i2. ° ... 

Carbon monoxide is also known to insert into metal alkoxides (M—OR), di-alkylamides (M—NR2), and some hydroxymethyls (M—CH2OH). For the reaction of the alkoxide (PPh3)2Ir(CO)(OMe) with CO the intermediate [Ir(CO)3(PPh3)2]+ OMe has been identified, and the insertion therefore proceeds via external nucleophilic attack of OMe" on Ir—CO rather than intramolecular OMe migration. True intramolecular transfer is, however, evident for (dppe)PtMe(OMe) where the rate of OMe migration is much faster than for Me migration, to give (dppe)PtMe(COOMe). 

Insertion reactions involving metal alkoxides are also known. For example, carbon dioxide is known to react with some metal alkoxides as shown in equation (12). The formation of a bidentate ligand is a significant thermodynamic driving force for some of these reactions. The isoelectronic aryl and alkyl isocyanates and carbodiimides can react similarly. Insertion reactions involving alkenes and carbon monoxide are known for platinum alkoxides. 

Thus the hard oxygen bases react more readily with metal carbonyls than the softer bases. Alkoxide ions attack coordinated carbon monoxide to form alkoxy carbonyl complexes. This reaction (Eq. 2-75) has been observed for many complexes of the metals Mn, Re, Ee, Ru, Os, Co, Rh, Ir, Pd, Pt, and Hg. 

Insertion of carbon monoxide followed by reductive coupling is an old reaction that continues to be studied and developed. Examples of this reaction are the carbonylation of nickel dialkyl complexes to give ketones, " alkyl-alkoxides to yield esters, and alkyl-amides to give organic amides (Equation (79)). The carbonylation of the binuclear complex 145 leads to the formation of an isoquinolone ring with the elimination of one of the two Ni atoms, but no GO insertion occurs at the second metal moiety. Hydrolytic cleavage of the remaining Ni-G bond provides the free heterocyclic base (Scheme 45). ... 

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